"He was generous and came up with loads of suggestions to make the film more funny."

Capaldi shocked fans by making the announcement he was quitting during a BBC Radio 2 show with presenter Jo Whiley.

He said he will leave Doctor Who at the end of the year. "I feel it’s time to move on," he said.

He became the 12th actor to play The Doctor in 2013 and the forthcoming 10th series will be his last.

"I feel sad, I love Doctor Who, it is a fantastic programme to work on," he said. "I can't praise the people I work with more highly, but I have always been someone that did a lot of different things."

He said he was asked to stay on after his contract ran out, but he wanted to move on to other challenges.

The new series airs in spring and Capaldi said his final episode would be shown at Christmas.